Resource allocation method and apparatus for cooperative transmission of base stations in wireless communication system

ABSTRACT

A resource allocation method and apparatus whereby a master base station of a virtual cell having at least one slave base station for cooperative resource allocation to a mobile station in a wireless communication system are provided. The resource allocation method includes transmitting, to the slave base station, a resource allocation request message including information on the resource to be allocated to the mobile station, receiving a resource allocation response message including one of accept and reject indications to the resource allocation request from the slave base station, transmitting, to the mobile station, a resource allocation information including a result of resource allocation negotiation with the slave base station, and transmitting data to the mobile station in cooperation with the slave base station based on the resource allocation information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. § 119(a) of a Koreanpatent application filed on Jul. 27, 2012 in the Korean IntellectualProperty Office and assigned Ser. No. 10-2012-0082081, the entiredisclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system and,in particular, to a resource allocation method and apparatus forfacilitating the cooperative transmission of base stations in a wirelesscommunication system.

BACKGROUND

Mobile communication systems have been developed to provide subscriberswith voice communication services on the move. With the rapid advance oftechnologies, the mobile communication systems have evolved to supporthigh speed data communication services as well as standard voicecommunication services. However, the limited resources and the userrequirements for higher speed services in the current mobilecommunication system environment have spurred the evolution to moreadvanced mobile communication systems.

FIGS. 1A and 1B are diagrams illustrating resource allocation methodsfor communication between a Mobile Station (MS) and plural Base Stations(BSs) in wireless communication systems according to the related art.

Referring to FIG. 1A, the figure is directed to the case where theplural BSs 120 a, 120 b, and 120 c serve the MS 130 with the assistanceof the Base Station Controller (BSC) 100 cooperatively. That is, whenthe plural BSs 120 a, 120 b, and 12 c transmit downlink data to the MS130 and receive uplink data from the MS 130, the BSC 110 determines theradio resources for use in transmitting uplink data from the BSs 120 a,120 b, and 120 c to the MS 130 and downlink data from the MS 130 to theBSs 120 a, 120 b, and 120 c; and notifies the stations 120 a, 120 b, 120c, and 130 of the allocated resources. That is, the BSC 110 makes aresource allocation decision for data transmission from the plural BSs120 a, 120 b, and 120 c to the MS 130 and notifies the BSs 120 a, 120 b,and 120 c and MS 130 of the resource allocation result.

Referring to FIG. 1B, the figure is directed to the case whereindependent BSs 140 a, 140 b, and 140 c serve the MS 150 cooperativelyin a distributed resource allocation method. In this case, since the BSs140 a, 140 b, and 140 c make resource allocation decision to the MS 150independently, it is impossible for one BS to make a resource allocationdecision. Accordingly, the BSs 140 a, 140 b, and 140 c allocateresources to the MS 150 so as to minimize interference among each other.That is, the BS 1 140 a makes a resource allocation decision fordownlink and uplink transmission for the MS in consideration of theinterference to the BS 2 140 b and the BS 3 140 c so as to minimizeinterference thereto. In order to share the interference information,the BSs 140 a, 140 b, and 140 c may exchange resource allocationinformation, the BSs and MS may measure the interference in itself foruse in resource allocation. In the case of FIG. 1B, however, althoughthe plural BSs may allocate the radio resources capable of minimizinginterference there between, it is impossible for serving the MS usingany common radio resource.

As described above, in order for the plural BSs to serve an MScooperatively in the related-art method, it is necessary for a controlentity to determine the radio resource allocation method in acentralized manner (FIG. 1A) or for the base stations to make resourceallocation decision so as to minimize the interference there between ina distributed manner (FIG. 1B).

Accordingly, a need exists for a method and apparatus for allocatingresources and for facilitating cooperation among base stations in awireless communication system.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure to provide a method for determining a host and scheme ofallocating resource capable of allocating radio resource efficiently inthe cooperative communication of plural BSs with an MS.

In accordance with an aspect of the present disclosure, a resourceallocation method of a master base station of a virtual cell having atleast one slave base station for cooperative resource allocation to amobile station in a wireless communication system includes transmitting,to the slave base station, a resource allocation request messageincluding information on a resource to be allocated to the mobilestation, receiving a resource allocation response message including oneof accept and reject indications to the resource allocation request fromthe slave base station, transmitting, to the mobile station, a resourceallocation information including a result of resource allocationnegotiation with the slave base station, and transmitting data to themobile station in cooperation with the slave base station based on theresource allocation information.

In accordance with another aspect of the present disclosure, a resourceallocation method of a slave base station of a virtual cell having onemaster base station for cooperative resource allocation to a mobilestation in a wireless communication system includes receiving a resourceallocation request message including information on a resource to beallocated to the mobile station from the master base station,determining whether to accept or reject the resource allocation requestof the master base station, transmitting a resource allocation responsemessage including a determination result to the master base station, andtransmitting data to the mobile station in cooperation with the masterbase station using the resource determined through resource allocationnegotiation with the master base station.

In accordance with another aspect of the present disclosure, a resourceallocation method of a master base station of a virtual cell having atleast one slave base station for cooperative resource allocation to amobile station in a wireless communication system includes transmittingtransmissive data information for initiating resource allocationnegotiation to the slave base station, receiving a response messageincluding resource allocation information for data transmission to themobile station from the slave base station, and transmitting data to themobile station in cooperation with the slave base station based on theresource allocation information.

In accordance with another aspect of the present disclosure, a resourceallocation method of a slave base station of a virtual cell having amaster base station for cooperative resource allocation to a mobilestation in a wireless communication system includes initiating resourceallocation negotiation with the master base station upon receipt oftransmissive data information transmitted by the master base station,generating resource allocation information for data transmission to themobile station, transmitting a response message including the resourceallocation information to the master base station, and transmitting datato the mobile station in cooperation with the master base station basedon the resource allocation information.

In accordance with another aspect of the present disclosure, a masterbase station of a virtual cell having at least one slave base stationfor cooperative resource allocation to a mobile station in a wirelesscommunication system includes a wired/wireless interface unit to performwired/wireless communication with the mobile station and neighbor basestations, and a control unit which controls to perform transmitting, tothe slave base station, a resource allocation request message includinginformation on a resource to be allocated to the mobile station,receiving a resource allocation response message including one of acceptand reject indications to the resource allocation request from the slavebase station, transmitting, to the mobile station, a resource allocationinformation including a result of resource allocation negotiation withthe slave base station, and transmitting data to the mobile station incooperation with the slave base station based on the resource allocationinformation.

In accordance with another aspect of the present disclosure, a slavebase station of a virtual cell having one master base station forcooperative resource allocation to a mobile station in a wirelesscommunication system includes a wired/wireless interface unit to performwired/wireless communication with the mobile station and neighbor basestations, and a control unit which controls to perform receiving aresource allocation request message including information on a resourceto be allocated to the mobile station from the master base station,determining whether to accept or reject the resource allocation requestof the master base station, transmitting a resource allocation responsemessage including a determination result to the master base station, andtransmitting data to the mobile station in cooperation with the masterbase station using the resource determined through resource allocationnegotiation with the master base station.

In accordance with another aspect of the present disclosure, a masterbase station of a virtual cell formed along with at least one slave basestation for cooperative resource allocation to a mobile station in awireless communication system includes a wired/wireless interface unitto perform wired/wireless communication with the mobile station andneighbor base stations, and a control unit which controls to performtransmitting transmissive data information for initiating resourceallocation negotiation to the slave base station, receiving a responsemessage including a resource allocation information for datatransmission to the mobile station from the slave base station, andtransmitting data to the mobile station in cooperation with the slavebase station based on the resource allocation information.

In accordance with still another aspect of the present disclosure, aslave base station of a virtual cell having a master base station forcooperative resource allocation to a mobile station in a wirelesscommunication system includes a wired/wireless interface unit to performwired/wireless communication with the mobile station and neighbor basestations, and a control unit which controls initiating resourceallocation negotiation with the master base station upon receipt oftransmissive data information transmitted by the master base station,generating resource allocation information for data transmission to themobile station, transmitting a response message including the resourceallocation information to the master base station, and transmitting datato the mobile station in cooperation with the master base station basedon the resource allocation information.

In accordance with still another an aspect of the present disclosure,one of plural base stations is determined as a logical master basestation and the others as logical slave base stations such that themaster base station performs a negotiation and a determination procedurefor resource allocation to the mobile terminal. Any of the plural basestations can work as the master base station, the master base stationcan be changed as the mobile station moves, and the master base stationcan be differentiated from a certain centralized preset base stationcontrol apparatus.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIGS. 1A and 1B are diagrams illustrating resource allocation methodsfor communication between a Mobile Station (MS) and plural Base Stations(BSs) in wireless communication systems according to the related art;

FIG. 2 is a diagram illustrating master-slave relationships among pluralBSs and MSs for supporting cooperative communication according to anembodiment of the present disclosure;

FIG. 3 is a signal flow diagram illustrating a resource allocationnegotiation method for data transmission with a slave BSs' resourcesbetween master and slave BSs according to an embodiment of the presentdisclosure;

FIGS. 4A and 4B are diagrams illustrating principles of avoidingresource conflict occurring in a resource allocation negotiationprocedure in a resource allocation method according to an embodiment ofthe present disclosure;

FIGS. 5A and 5B are signal flow diagrams illustrating a procedure for amaster BS to acquire radio channel information between plural BSs of avirtual cell and an MS for supporting the resource allocationnegotiation method of FIGS. 3, 4A, and 4B according to an embodiment ofthe present disclosure;

FIG. 6 is a signal flow diagram illustrating a resource allocationnegotiation method for data transmission with a slave BSs' resourcesbetween master and slave BSs according to another embodiment of thepresent disclosure;

FIGS. 7A and 7B are diagrams illustrating principles of avoidingresource conflict occurring in a resource allocation negotiationprocedure in a resource allocation method according to anotherembodiment of the present disclosure;

FIGS. 8A and 8B are signal flow diagrams illustrating a procedure ofacquiring radio channel information between MS and master and slave BSsbased on a downlink reference signal according to another embodiment ofthe present disclosure;

FIGS. 9A and 9B are signal flow diagrams illustrating a procedure ofacquiring radio channel information between MS and master and slave BSsbased on an uplink reference signal according to another embodiment ofthe present disclosure;

FIG. 10 is a flowchart illustrating a master BS procedure of a resourceallocation method according to an embodiment of the present disclosure;

FIG. 11 is a flowchart illustrating a slave BS procedure in a resourceallocation method according to an embodiment of the present disclosure;

FIG. 12 is a flowchart illustrating a master BS procedure in a resourceallocation method according to an embodiment of the present disclosure;

FIG. 13 is a flowchart illustrating a slave BS procedure in a resourceallocation method according to another embodiment of the presentdisclosure;

FIG. 14 is a block diagram illustrating a configuration of a master BSaccording to an embodiment of the present disclosure;

FIG. 15 is a block diagram illustrating a configuration of a slave BSaccording to an embodiment of the present disclosure;

FIG. 16 is a block diagram illustrating a configuration of a master BSaccording to another embodiment of the present disclosure;

FIG. 17 is a block diagram illustrating a configuration of a slave BSaccording to another embodiment of the present disclosure; and

FIG. 18 is a block diagram illustrating a configuration of an MSaccording to an embodiment of the present disclosure.

The same reference numerals are used to represent the same elementsthroughout the drawings.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

FIG. 2 is a diagram illustrating master-slave relationships among pluralBase Stations (BSs) and Mobile Stations (MS) for supporting cooperativecommunication according to an embodiment of the present disclosure.

Referring to FIG. 2, it is assumed that three BSs (BS1, BS2, and BS3)form the respective virtual cells for providing wireless data serviceand are capable of transmitting and receiving data to and from the MScooperatively. That is, the MS is capable of receiving or transmittingdata from or to the three BSs simultaneously. The MS is also capable ofreceiving or transmitting data from or to one or two of the BSsselectively. The MS may receive the same data from the three BSssimultaneously. The three BSs may transmit the same data or differentdata segments that can be combined into the original data at the MS.Although the description may be directed to a certain case, the presentdisclosure is not limited thereto. In order for the MS to support thecooperative data communication with the three BSs, it is necessary toestablish the master-slave relationship among the BSs. The master BS hasthe determination right in resource allocation negotiation for datacommunication between the MS and the three BSs. The slave BS negotiatesresource allocation for serving the MS with the master BS andcommunicates data with the MS based on the resource allocationinformation determined by the master BS.

A description of the method for establishing master-slave relationshipaccording to an embodiment of the present disclosure is made hereinafterwith reference to FIG. 2.

If it powers on, the MS performs a measurement to check the radio signalquality between the MS and each of the BSs. It is possible to measurethe signal quality based on a signal strength, a Signal to Noise Ratio(SNR), or a Signal to Interference and Noise Ratio (SINR) of thesynchronization signal, such as preambles, transmitted by the BSs. TheMS performs network entry to the BS having the best signal quality as aresult of measurement. Once the network entry procedure has completedsuccessfully, the BS to which the MS has connected becomes the masterBS. The master BS receives signal quality report from the MS andconfigures the BSs capable of communicating with the MS as slave BSs.The master BS to which the MS has performed the network entry procedureand the slave BS configured by the master BS establish a virtual cellwhich provides the MS with the communication service cooperatively.

Assuming that BS1 is the master BS of the MS at time T1 and BS2 and BS3are slave BSs in FIG. 2, the BS1, BS2, and BS3 establishes a virtualcell for providing the MS with the data communication servicecooperatively under the control of the BS1.

Meanwhile, if the signal quality of the BS2 becomes better than those ofBS3 and BS3 due to the roaming of the MS at time T2, the BS1 hands overthe mastery right to BS2. Likewise, if the signal quality of the BS3becomes better than those of BS1 and BS3 due to the roaming of the MS attime T3, BS2 hands over the mastery right to BS3.

That is, in the case that plural BSs (BS1, BS2, and BS3) are capable ofestablishing a virtual cell for cooperative data communication, one ofthe BSs establishing the virtual cell becomes the master BS and theothers slave BSs.

In an embodiment, the master BS may be the BS selected among the BSsestablishing the virtual cell based on their signal qualities measuredby the MS as in FIG. 2, the serving BS managing the MS information onthe Medium Access Control (MAC) as layer 2 among the BSs establishingthe virtual cell, or the BS selected by a Gateway operating at a levelhigher than BSs or a network entity controlling BSs. Although there arevarious approaches for determining the master BS, the present disclosureis directed to a radio resource allocation method based on therelationship between master and slave BSs regardless of how the masterand slave BSs are configured.

FIG. 3 is a signal flow diagram illustrating a resource allocationnegotiation method for data transmission with a slave BSs' resourcesbetween master and slave BSs according to an embodiment of the presentdisclosure.

Referring to FIG. 3, assuming a virtual cell established by one maser BS310 and one or more slave BSs 320 a, 320 b, and 320 c; the master BS 310is capable of performing cooperative resource allocation to the MS 330as follows.

Assuming that the master BS 310 has the radio channel information andresource headroom information on all BSs forming the virtual cell, themaster BS 310 performs negotiation for resource allocation with theslave BSs 320 a, 320 b, and 320 c. The negotiation process is describedhereinafter.

In an embodiment, the master BS 310 sends a resource allocation requestmessage to the slave BSs 320 a, 320 b, and 320 c at operation S310. Theresource allocation request message may include radio resourceinformation requesting the slave BSs 320 a, 320 b, and 320 c to allocateresource to the MS, i.e., the information on the frequency and timeresources. Assuming an OFDM system, the radio resource informationincludes the number of OFDM Resource Blocks (RBs) and OFDM sub-channeland symbol configuration.

In this embodiment, the master BS 310 requests the slave BSs 320 a, 320b, and 320 c to allocate specific radio resources to the MS. In thiscase, the master BS 310 may inform the slave BSs 320 a, 320 b, and 320 cof specific OFDM sub-channels and OFDM symbols.

According to an embodiment of the present disclosure, the master BS 310is capable of transmitting the data addressed to the MS 330 to the slaveBSs 320 a, 320 b, and 320 c along with the resource allocation message.In the case that the data to be transmitted to the MS 330 are retainedin the slave BSs 320 a, 320 b, and 320 c, the master BS may inform theslave BSs 320 a, 320 b, and 320 c of specific data.

If the resource allocation message is received, each of the slave BSs320 a, 320 b, and 320 c sends the master BS 310 a resource allocationresponse message including the information on whether to accept orreject the resource allocation request or the available RBs among theRBs requested by the master BS 310 at operation S320. Each of the slaveBSs 320 a, 320 b, and 320 c determines whether to accept entirely orpartially or reject the resource allocation request from the master BS310 in consideration of resource headroom, resource reserved for otherMSs, interference on the resources requested by the master BS 310, andradio channel status. Detailed description thereon is made hereinafter.

If the resource allocation response message is received from at leastone of the slave BSs 320 a, 320 b, and 320 c, the master BS 310 sends aresource allocation confirmation message to the slave BSs 320 a, 320 b,and 320 c at operation S330. If the data to be transmitted to the MS 330are not shared with the slave BSs 320 a, 320 b, and 320 c until now, themaster BS 310 may transmit the data addressed to the MS to the slave BSs320 a, 320 b, and 320 c along with the resource allocation confirmationmessage at operation S330.

In an embodiment, the resource allocation confirmation message includesthe information on whether the resource allocation is accepted orrejected finally or the scheduling information on theallocation-confirmed resource. The transmission of the resourceallocation confirmation message may be skipped depending on theinformation included in the resource allocation response message.

The master BS 310 generates the resource allocation information (orscheduling information) at operation S340 by reflecting the resourceallocation negotiation procedure with the slave BSs 320 a, 320 b, and320 c that is performed through operations S310 to S330. The master BS310 sends the MS 330 the resource allocation information at operationS350. Afterward, the master BS 310 may transmit the data to the slaveBSs 320 a, 320 b, and 320 c at operation S360 after the end of theresource allocation negotiation procedure.

Then, the MS 330 is capable of transmitting and receiving data with theBSs forming the virtual cell cooperatively. A detailed description onthe radio data transmission is omitted herein. However, all availablecooperative downlink and uplink transmissions of plural BSs can beapplied in the present disclosure.

FIGS. 4A and 4B are diagrams illustrating principles of avoidingresource conflict occurring in a resource allocation negotiationprocedure in a resource allocation method according to an embodiment ofthe present disclosure.

Referring to FIGS. 4A and 4B, the figures are directed to a method forovercoming the overlap of the resources requested by plural master BSsto a slave BS.

One BS may serve a group of MSs as the master BS and another group ofMSs as the slave BS. If it belongs to more than one virtual cell, the BSmay receive the resource allocation request message from the master BSsof the respective virtual cells.

In this case, the resource region to be allocated by the BS as themaster BS and the resource region requested from other master BS mayoverlap. At this time, the slave BS may perform the conflict resolutionto resolve the resource conflict situation.

That is, when the Nth BS (BS#N) receives the resource allocationrequests from the three master BSs as shown in FIG. 4A, the BS#N maydetermine whether the requested resources are overlapped. If there isany overlapped resource region, the BS#N may control such that therequested resource regions are overlapped neither among each other, norwith the resource region available for the BS#N to allocate. Then, theBS#N notifies the master BSs requested for the resource allocation ofthe arbitrated RB (resource region) information.

Each of the master BSs may request the slave BSs to allocate resource tothe MS based on the arbitrated resource allocation information, and theslave BS may accept or reject the request to avoid the conflict betweenthe resource region to be allocated by the master BS and among the slaveBSs.

If the master BS accepts the resource allocation region changed by theslave BS, the slave BS has to confirm at least partial or entire of theresponded RBs. If the master BS changes the resource allocation again,the negotiation between the master and slave BSs for resource allocationto the MS may repeat infinitely, the master BS has to accept or rejectthe resource allocation finally to end the negotiation procedure.

The resource allocation request, the resource allocation response, andthe resource allocation confirmation messages that are used in thenegotiation procedure for resource allocation and conflict avoidancebetween the master and slave BSs in FIGS. 3 and 4A and 4B may includethe following information. The information enumerated herein as theinformation carried in the above messages is information proposed in anembodiment of the present disclosure, but is not limited thereto.

Tables 1A and 1B show the information included in the resourceallocation request message.

TABLE 1A Information Description Number of RBs Information on number ofRBs RB index Information on RB number Frame or subframe Information onframe or subframe number as time index resource information of physicallayer

Meanwhile, in the case that the master BS sends the slave BS theinformation on the data to be served to the MS cooperatively in theresource allocation request message, the following information mayfurther be included.

TABLE 1B Information Description MAC unit data (optional) ARQ sequencenumber or MAC PDU sequence number

Table 2 shows the information included in the resource allocationresponse message. The information on the RBs accepted by the slave BSincludes the information on the RBs replaced by the slave BS forconflict avoidance as well as the RBs requested by the master BS.

TABLE 2 Information Description Resource allocation Acknowledgementcorresponding to resource request accept/reject allocation requestNumber of accepted Information on number of RBs accepted by slave RBsAccepted RB index Information on RB number accepted by slave Acceptedframe or Information on frame or subframe number in RB subframe index

Table 3A shows the information included in the resource allocationconfirmation message. The confirmed resource allocation information,i.e., scheduling information, may be included in the response messagetransmitted from the master BS to the slave BS.

TABLE 3A Information Description Response message accept/rejectAcknowledgement corresponding to response message of slave Resourceallocation MCS Modulation and Coding scheme information information(physical layer scheduling information for transmitting data to MS usingRB) HARQ info HARQ channel information Cooperative Cooperativetransmission scheme Transmission (Joint transmission) Scheme BeamformingMultiple Antenna Transmission scheme (MIMO, Digital/Analog beamforming)Resource Information on RB and radio allocation frame or subframeinformation

Table 3B shows the information included in the scheduling messagecarrying the resource allocation information generated by the master BSbased on the result of negotiation between the master and slave BSs.Unlike the legacy scheduling message carrying downlink and uplinkscheduling information, this message includes plural BS IDs and per-BSresource allocation information as shown in Table 3B since plural BSsjoin the data transmission.

TABLE 3B Information Description MS ID ID (identifier) of MS receivingor transmitting data BS ID IDs of BSs (master and slave) joining thecooperative communication Per-BS resource MCS, HARQ info., cooperativetransmission scheme, allocation beamforming scheme, and resourceallocation information information determined in Table 3A

FIGS. 5A and 5B are signal flow diagrams illustrating a procedure for amaster BS to acquire radio channel information between plural BSs of avirtual cell and an MS for supporting the resource allocationnegotiation method of FIGS. 3, 4A, and 4B according to an embodiment ofthe present disclosure.

Referring to FIG. 5A, the figure is a signal flow diagram illustratingthe procedure for the master BS to acquire radio channel informationbetween the plural BSs of a virtual cell and the MS based on downlinkreference signals according to an embodiment of the present disclosure.

In FIG. 5, each of the BSs 510, 520 a, 520 b, and 520 c forming thevirtual cell transmits Reference Signal (RS) including a digital bitsequence for radio channel estimation at operation S510. Then, the MS530 receives and decodes the RS to measure the quality of the signalpropagated over a radio channel at operation S520. The measured signalquality may be indicated by a Signal Strength, a SNR, or a SINR.

The signal quality measured by the MS 530 based on the RS is referred toas Channel Quality Information (CQI), and the MS 530 sends theBS-specific CQI information to the master BS 510 at operation S530.

Then, the master BS 510 reconfigures the virtual cell or assigns radioresource for cooperative communication to the respective slave BSs 520a, 520 b, and 520 c based on the BS-specific CQI information.

Referring to FIG. 5B, the figure is a signal flow diagram illustratingthe procedure for the master BS to acquire radio channel informationbetween the plural BSs of a virtual cell and the MS based on uplinkreference signals according to an embodiment of the present disclosure.

In FIG. 5B, the MS 530 transmits Reference Signal (RS) including adigital bit sequence for radio channel estimation at operation S540. TheBSs 510, 520 a, 520 b, and 520 c receive and decode the RS to measurethe quality of the signal propagated over a radio channel at operationS550. The measured signal quality may be indicated by a Signal Strength,a SNR, or a SINR.

The slave BSs 520 a, 520 b, and 520 c among the BSs forming the virtualcell sends the measured CQIs to the master BS 510 at operation S560.

FIG. 6 is a signal flow diagram illustrating a resource allocationnegotiation method for data transmission with a slave BSs' resourcesbetween master and slave BSs according to another embodiment of thepresent disclosure.

Referring to FIG. 6, in the virtual cell formed along with at least oneBS, if one master BS and plural slave BSs exist, the master BS iscapable of performing cooperative resource allocation to the MS asfollows.

Although this embodiment is directed to the case where the master BS hasthe radio channel information between the MS and the respective BSsforming the virtual cell and the resource headroom information on theavail resources for data transmission, it is possible to perform theresource allocation negotiation with the slave BSs. The resourceallocation negotiation is performed as follows.

The master BS 610 sends a resource allocation request message to theslave BSs 620 a, 620 b, and 620 c at operation S610. The resourceallocation request message may include the information on the data sizefor the master BS 610 to allocate the resource through the slave BSs 620a, 620 b, and 620 c. According to an embodiment of the presentdisclosure, the resource allocation request message may include a partor entire of the information on the data transmission scheme. Accordingto an embodiment of the present disclosure, the master BS 610 maytransmit the data itself addressed to the MS 630 through the cooperativetransmission with the slave BSs 620 a, 620 b, and 620 c.

That is, in the case that the resource allocation message includes theinformation on the data size or data transmission scheme, the datacorresponding to the data size may be retained in the slave BS alreadyor received from the master BS after the resource allocation negotiationother than at the current time of resource allocation request. In thecase that the master BS transmits the data itself other than theresource allocation request message, the slave BS becomes aware of thesize of the data and thus there is no need of transmitting the data sizeinformation in the resource allocation request message redundantly.

In the above-described embodiment, the master BS 610 sends the resourceallocation request message or the data itself to request the slave BSs620 a, 620 b, and 620 c for cooperative communication resourceallocation, and this may be referred to as transmissive data informationherein. In this embodiment, the master BS 610 sends the slave BSs 620 a,620 b, and 620 c the transmissive data information to request for thecooperative communication resource allocation which includes theresource allocation request message or the data itself.

Afterward, each of the slave BSs 620 a, 620 b, and 620 c sends aresponse message to the master BS 610 in response to the resourceallocation request message or the data itself at operation S630. As aprecondition for this, if the slave BS 620 a, 620 b, and 630 c acceptthe resource allocation request, they generate the resource allocationinformation for the data transmission requested by the master BS 610.The slave BSs 620 a, 620 b, and 620 c send the master BS 610 theresponse message including the resource allocation information. In thecase that the resource allocation request message includes a part ofdata transmission scheme information or no data transmission schemeinformation, the response message may include a part or entire of thedata transmission scheme information.

However, the resource allocation request of the master BS 610 isrejected, the slave BSs 620 a, 620 b, and 620 c sends the responsemessage indicating the reject to the master BS 610 in response to theresource allocation request message.

The master BS 610 receives the response message from the slave BSs 620a, 620 b, and 620 c in response to the resource allocation requestmessage, generates, when the response message includes indication ofaccept, the final resource allocation information for the data to betransmitted to the MS based on the resource allocation informationincluded in the response message, and sends the MS 630 the finalresource allocation information at operation S670. Then, the MS 630communicates data with the master and slave BSs 610, 620 a, 620 b, and620 c of the virtual cell based on the received resource allocationinformation at operation S680.

In the case that the response message received from the slave BSincludes the indication of reject to the resource allocation request,the master BS 610 generates the final resource allocation informationfor data transmission to the MS with the exception of the resourceallocation information on the rejected slave BS. The master BS 610 sendsthe MS 630 the final resource allocation information at operation S670.Then, the MS 630 communicates data with the master and slave BSs of thevirtual cell, with the exception of the rejected slave BS, based on thereceived resource allocation information at operation S680.

In the above case, the resource allocation negotiation procedure betweenthe master and slave BSs end at this operation.

However, the resource region of the RBs intended by the master BS 610may conflict with the resource of the RBs indicated by the slave BSs 620a, 620 b, and 620 c depending on the cooperative transmission scheme. Inthis case, there is a need of transmitting a confirmation message to theslave BSs 620 a, 620 b, and 620 c in response to the resource allocationresponse message. The resource region conflict and how to overcome theresource region conflict are described in detail later with reference toFIG. 7.

If it is necessary for the master BS 610 to send the slave BSs 620 a,620 b, and 620 c, the confirmation message additionally at operationS640, a resource conflict has occurred at the resource region intendedby the master BS 610. The confirmation message transmitted from themaster BS 610 to the slave BSs 620 a, 620 b, and 620 c may include theinformation on when the response message is accepted or rejected. If theaccept/reject information is included, the resource allocationnegotiation procedure between the master and slave BSs end.

However, even when the master BS 610 accepts the response message, it ispossible for the master BS 610 to modify the RB's resource allocationinformation in the response message for the reason of resource conflict.In this case, the RB's resource allocation information modified by themaster BS 610 may be transmitted to the slave BSs in the confirmationmessage at operation S640. At this time, the master BS 610 has toreceive a decision-making message including the final accept or rejectin response to the confirmation message including the modified RB'sresource allocation information from the respective slave BSs atoperation S650.

From the view point of a slave BS, if the confirmation message isreceived from the maser BS 610, the slave BS checks the modified RB'sresource allocation information included in the confirmation message anddetermines whether to accept or reject the modification. The slave BSsends the decision-making (acknowledgement) message including theindication of acceptance or rejection to the master BS 610 at operationS650.

The master BS 610 receives the decision-making message from the slaveBSs and ends the resource allocation negotiation procedure between themaster and slave BSs 610, 620 a, 620 b, and 620 c.

If the resource allocation negotiation procedure between the master andslave BSs 610, 620 a, 620 b, and 620 c ends, and if the slave BSs 620 a,620 b, and 620 c have no data to be transmitted to the MS 630, themaster BS 610 may transmit the data to the slave BSs 610, 620 a, 620 b,and 620 c at operation S660 after the end of the resource allocationnegotiation procedure.

Afterward, the master BS 610 sends the MS 630 the final resourceallocation information determined through the resource allocationnegotiation procedure with one or more slave BSs 610, 620 a, 620 b, and620 c at operation S670. Then, the MS 630 is capable of radio datacommunication with plural BSs cooperatively.

Embodiments of the radio data transmission procedure are not describedin detail herein. However, all available downlink and uplink cooperativecommunication of plural BSs can be applied in the present disclosure.

FIGS. 7A and 7B are diagrams illustrating principles of avoidingresource conflict occurring in a resource allocation negotiationprocedure in a resource allocation method according to anotherembodiment of the present disclosure.

Referring to FIGS. 7A and 7B, the figures are directed to the method forovercoming the overlap of the resources requested by plural slave BSs tothe master BS.

A BS may serve a group of MSs as the master BS and another group of MSsas a slave BS in a virtual cell. If it belongs to one or more virtualcells, the master BS receives the resource allocation request messagefrom the slave BSs of plural virtual cells as described with referenceto FIG. 6.

When the master BS intends to user a resource region composed of RBsdifferent from those of the slave BSs for transmitting data to the MS,the master BS's resource region may overlap with the resource region ofthe RBs indicated in the response message from the slave BSs or theresource regions of RBs of slave BSs overlap among each other.

At this time, the BS may perform the conflict resolution to resolve theresource conflict situation.

Referring to FIG. 7A, the Nth BS (BS#N) checks the resource allocationinformation included in the resource allocation response message fromthe three slave BSs to determine whether the resource regions areoverlapped. If there is any overlap between the resource regions, theBS#N may control such that the requested resource regions are overlappedneither among each other nor with the resource region available for theBS#N to allocate.

Then, in embodiments, the BS#N notifies the slave BSs of the arbitratedRB (resource region) information. If the slave BS received the resourceallocation information modified by the BS#N, i.e., the master BSmodifies the resource allocation information again, the negotiationbetween the master and slave BSs for resource allocation to the MS mayrepeat infinitely, and the slave BS has to accept or reject the resourceallocation finally to end the negotiation procedure.

The resource allocation request, the resource allocation response, theresource allocation confirmation, and the decision-making messages thatare used in the negotiation procedure for resource allocation andconflict avoidance between the master and slave BSs in FIGS. 6 and 7Aand 7B may include the following information according to an embodimentof the present disclosure.

Table 4 shows the information included in the resource allocationrequest message.

TABLE 4 Information Description Data size Information on the size (byte)of data to be transmitted to the MS through cooperative communicationbetween master and slave BSs Data Data transmission informationincluding MCS, HARQ info, transmission Cooperative transmission scheme,Beamforming scheme, scheme etc.

Table 5 shows the information included in the resource allocationresponse message.

TABLE 5 Information Description Resource allocation Acknowledgementcorresponding to resource request accept/reject allocation request RBindex Accepted RB number information Frame or subframe Frame or subframeinformation of accepted RB index Data transmission Data transmissionscheme information including scheme MCS, HARQ info, Cooperativetransmission scheme, Beamforming scheme, etc.

Table 6 shows the information included in the resource allocationconfirmation message.

TABLE 6 Information Description Response message Acknowledgementcorresponding to information accept/reject included in response messagefrom slave BS RB index RB number information changed by master BS Frameor subframe Frame or subframe number information of RB index changed bymaster BS

Table 7 shows the information included in the decision-making message.

TABLE 7 Information Description Confirmation message Acknowledgementcorresponding to accept/reject information included in the confirmationmessage from master BS

FIGS. 8A and 8B are signal flow diagrams illustrating a procedure ofacquiring radio channel information between MS and master and slave BSsbased on a downlink reference signal according to another embodiment ofthe present disclosure.

Referring to FIG. 8A, the figure is a signal flow diagram illustratingthe procedure of acquiring the radio channel information between MS andplural BSs forming a virtual cell based on downlink reference signalaccording to an embodiment of the present disclosure.

Each of the BSs 810, 820 a, 820 b, and 820 c forming the virtual celltransmits Reference Signal (RS) including a digital bit sequence forradio channel estimation at operation S810. Then, the MS 830 receivesand decodes the RS to measure the quality of the signal propagated overa radio channel at operation S820. The measured signal quality may beindicated by a Signal Strength, a SNR, or a SINR. The signal qualitymeasured by the MS 830 based on the RS is referred to as CQI.

The MS 830 sends the BS-specific CQI information to the master BS 810 atoperation S530. Then, the master BS 810 sends the BS-specific CQIinformation to the slave BSs 820 a, 820 b, and 820 c at operation S840.

Referring to FIG. 8B, the figure is a signal flow diagram illustratingthe procedure for acquiring radio channel information between MS andplural BSs forming a virtual cell based on downlink reference signalsaccording to another embodiment of the present disclosure.

The radio channel information acquisition procedure of FIG. 8B differsfrom that of FIG. 8A in that the MS 830 reports the BS-specific CQIinformation to the respective BSs directly at operation S850 rather thanreports to only the master BS 810.

Since the radio channel information acquisition procedures of FIGS. 8Aand 8B are identical with each other with the exception of thisoperation of reporting the CQI information, detailed description thereonis omitted herein.

FIGS. 9A and 9B are signal flow diagrams illustrating a procedure ofacquiring radio channel information between MS and master and slave BSsbased on an uplink reference signal according to another embodiment ofthe present disclosure.

Referring to FIG. 9A, the figure is a signal flow diagram illustratingthe procedure of acquiring radio channel information between MS andmaster and slave BSs forming a virtual cell according to anotherembodiment of the present disclosure.

The MS 930 transmits Reference Signal (RS) including a digital bitsequence for radio channel estimation at operation S910. Then, the BSs910, 920 a, 920 b, and 920 c receive and decode the RS to measure thequality of the signal propagated over a radio channel at operation S920.The measured signal quality may be indicated by a Signal Strength, aSNR, or a SINR.

Referring to FIG. 9B, the figure is a signal flow diagram illustratingthe procedure of acquiring radio channel information between MS andmaser and slave BSs forming a virtual cell according to anotherembodiment of the present disclosure.

The radio channel information acquisition procedure of FIG. 9B differsfrom that of FIG. 9A in that the CQI information measured by the slaveBSs 920 a, 920 b, and 920 c are reported to the master BS at operationS930.

FIG. 10 is a flowchart illustrating a master BS procedure of a resourceallocation method according to an embodiment of the present disclosure.

Referring to FIG. 10, the master BS first forms a virtual cell with atleast one slave BS at operation S1010. The virtual cell is formed suchthat the master and slave BSs communicate data with the MScooperatively. Although the master BS is the BS to which the MS hasperformed network entry procedure in the above description, the presentdisclosure is not limited thereto.

Next, the master BS acquires radio channel information between the MSand the respective BSs at operation S1020. The radio channel informationmay be CQI measured by the MS. In embodiments, the master BS may becapable of receiving the CQIs measured by the MS for the respectiveslave BSs in downlink and the CQIs measured by the respective slave BSsin uplink.

In embodiments, the master BS may perform resource allocationnegotiation procedure with the slave BSs under the assumption that ithas the radio channel information between the MS and the respective BSsforming the virtual cell and the resource headroom information of theslave BSs.

For this purpose, the master BS sends the slave BSs the resourceallocation request message including the information on the resourcewhich recommended for the slave BSs to allocate to the MS at operationS1030.

Next, the master BS receives the resource allocation response messageincluding the information on whether to accept or reject the resourceallocation request at operation S1040. If necessary, the master BS sendsthe slave BS a resource allocation confirmation message at operationS1050. In this case, the resource allocation confirmation message mayinclude the information on whether to accept or reject the resourceallocation response message finally.

Next, the master BS sends the MS the resource allocation informationdetermined through resource allocation negotiation procedure with theslave BSs at operation S1060.

Then, the master BS transmits the data to the MS in cooperation with theslave BSs based on the resource allocation information at operationS1070.

FIG. 11 is a flowchart illustrating a slave BS procedure in a resourceallocation method according to an embodiment of the present disclosure.

Referring to FIG. 11, the slave BS first receives a resource allocationrequest message from the master BS of the virtual cell at operationS1105. Next, the slave BS checks the resource requested by the master atoperation S1110.

The slave BS determines whether to accept the resource allocationrequest entirely or partially or reject the resource allocation requestin consideration of its resource headroom status, conflict between theresource reserved for other MSs and the resource requested by the masterBS, and radio channel status at operation S1115.

If it is determined to reject the request, the slave BS generates aresource allocation response message including the reject indication atoperation S1120 and sends the resource allocation response message tothe master BS at operation S1145.

Otherwise, if it is determined to accept the resource allocation requestfrom the master BS at operation S1115, the slave BS determines whetherthere is any conflict between the resources requested by plural masterBSs at operation S1125. If there is no conflict, the slave BS generatesthe resource allocation response message including accept indication atoperation S1130 and sends the resource allocation response message tothe master BS at operation S1145.

Otherwise, if there is any conflict, the slave BS arbitrates to resolvethe resource conflict at operation S1135 and generates the resourceallocation response message including the arbitrated resource allocationinformation at operation S1140. The slave BS sends the resourceallocation response message to the master BS at operation S1145.

According to an embodiment of the present disclosure, the slave BS mayreceive a resource allocation confirmation message including the masterBS's final decision on whether to accept or reject the resourceallocation arbitrated by the slave BS (not shown), the confirmationmessage being transmitted in response to the response message.

After transmitting the resource allocation response message, the slaveBS receives the finally decided resource allocation information from themaster BS at operation S1150. Then, the slave BS serves the MS incooperation with the master BS based on the received resource allocationinformation in operation S1155.

FIG. 12 is a flowchart illustrating a master BS procedure in a resourceallocation method according to an embodiment of the present disclosure.

Referring to FIG. 12, the embodiment reflected therein differs from theembodiment in FIG. 10. In the embodiment of FIG. 10, the master BSrequests the slave BS to allocate the resource recommended by the masterBS to the MS. In the embodiment of FIG. 12, the master BS sends theslave BS only the information on the data addressed to the MS to beserved cooperatively (data size and transmission scheme) and thus theresource allocation procedure is dominated by the slave BS.

In FIG. 12, the master BS forms a virtual cell with at least one slaveBS at operation S1205.

The master BS sends the slave BS the transmissive data information atoperation S1210. The transmissive data information may be the allocationrequest message including the information on the size of data to betransmitted to the MS. The resource allocation request message mayinclude the information on the data transmission scheme entirely orpartially. According to an embodiment of the present disclosure, thetransmissive data information may be the data itself to be transmittedto the MS.

The master BS receives the resource allocation response message from theslave BS and checks the content of the response message at operationS1215.

The master BS determines whether the response message includes theindication of accepting the resource allocation request at operationS1220. If the resource allocation request is rejected, the master BSgenerates the resource allocation information in which the slave BSrejected the resource allocation request is ruled out at operationS1225.

Otherwise, if the resource allocation request is accepted, the master BSdetermines whether there is any conflict among the resources accepted bythe plural slave BSs at operation S1230. If no resource conflict occurs,the master BS generates the final resource allocation information andsends it to the MS at operation S1232.

If there is any resource conflict, the master BS arbitrates to avoidoverlap among the resource regions recommend by the slave BSs atoperation S1235. Then, the master BS transmits the confirmation messageincluding the arbitrated resource allocation information to the slaveBSs.

Next, in operation S1245, the master BS receives the decision-makingmessage from the slave BSs in response to the confirmation message sentincluding the arbitrated resource allocation in operation S1240.

Through this, the resource allocation negotiation procedure between themaster and slave BSs ends, and the master BS sends the MS the resourceallocation information determined through the negotiation procedure atoperation S1250.

Finally, the master BS serves the data communication of the MS incooperation with the slave BSs based on the resource allocationinformation at operation S1255.

FIG. 13 is a flowchart illustrating a slave BS procedure in a resourceallocation method according to another embodiment of the presentdisclosure.

Referring to FIG. 13, the slave BS receives the transmissive datainformation from the master BS of the virtual cell at operation S1305.The transmissive data information may be the resource allocation requestmessage including the information on the size of data to be transmittedto the MS and data transmission scheme. The transmissive datainformation may be the data itself to be transmitted to the MS.

Then, the slave BS determines whether to accept or reject the resourceallocation request from the master BS at operation S1310. If it isdetermined to reject the resource allocation request, the master BSgenerates the resource allocation response message including the rejectindication at operation S1315 and sends the master BS the resourceallocation response message at operation S1320.

If it is determined to accept the resource allocation request, the slaveBS generates the resource allocation response message including theresource allocation information and data transmission scheme informationat operation S1325. The slave BS sends the master BS the resourceallocation response message at operation S1330.

In the case that the resource region of the RBs indicated in theresource allocation information generated by the plural slave BSsconflict, the slave BS may receive a resource allocation confirmationmessage to resolve the conflict at operation S1335. Then, the slave BSdetermines whether to accept or reject the resource allocationmodification request included in the confirmation message at operationS1340.

If it is determined to reject the resource allocation modificationrequest of the master BS, the slave BS generates the decision-makingmessage including the reject indication at operation S1345. Next, theslave BS sends the master BS the decision-making message at operationS1355.

Otherwise, if it is determined to accept the resource allocationmodification request of the master BS, the slave BS generates thedecision-making message including the accept indication at operationS1350. Next, the slave BS sends the master BS the decision-makingmessage at operation S1355.

Finally, the slave BS transmits data to the MS in cooperation with themaster BS and other slave BSs according to the final resource allocationinformation at operation S1360.

FIG. 14 is a block diagram illustrating a configuration of a master BSaccording to an embodiment of the present disclosure.

Referring to FIG. 14, the wired/wireless interface unit 1410 provides awired and/or wireless interface for the master BS to communicate withthe MS or a higher layer network node through wired or wireless channel.In detail, the wireless interface is provided with a physical means forthe master BS to communicate control signal and data with the MS throughradio communication, and the wired interface is provided with a wiredcommunication means connected to a neighbor BS, a Mobility ManagementEntity (MME), and a Serving Gateway.

According to an embodiment of the present disclosure, the control unit1420 controls such that the master BS forms a virtual cell with pluralslave BSs. The control unit 1420 controls to generate the resourceallocation information through resource allocation negotiation procedurewith the slave BSs and provides the data communication service to the MSin cooperation with the slave BSs. In order to accomplish this, thecontrol unit 1420 includes a virtual cell configurator 1420 a, aresource allocation information generator 1420 b, and a cooperativetransmission controller 1420 c.

The virtual cell configurator 1420 a configures a virtual cell includingthe master BS and at least one slave BS. The BSs forming the virtualcell may communication data with the MS cooperatively in a diversitymanner or a multiplexing manner. As described above, the master BS maybe the BS to which the MS has performed the network entry process, butnot limited thereto.

The resource allocation information generator 1420 b performs resourceallocation negotiation procedure with the slave BSs for providingcooperative data communication service to the MS. In order to accomplishthis, the resource allocation information generator 1420 b sends therespective slave BSs the resource allocation request message includingthe information on the resource for the slave BSs to allocate the MS.The resource allocation information generator 1420 b receives theresource allocation response message including the accept or rejectindication from the slave BSs in response to the resource allocationrequest message. The resource allocation information generator 1420 btransmits the resource allocation confirmation message, if necessary. Inthis case, the resource allocation confirmation message may include theinformation whether to accept or reject the resource allocation responsemessage transmitted by the slave BSs. The resource allocationinformation generator 1420 b controls to send the MS the resourceallocation information determined through the negotiation procedure withthe slave BSs.

The cooperative transmission controller 1420 c controls the master BS totransmit the data to the MS in cooperation with the slave BSs accordingto the resource allocation information.

FIG. 15 is a block diagram illustrating a configuration of a slave BSaccording to an embodiment of the present disclosure.

Referring to FIG. 15, the wired/wireless interface unit 1510 provides awired and/or wireless interface for the slave BS to communicate with theMS or a higher layer network node through wired or wireless channel. Indetail, the wireless interface is provided with a physical means for theslave BS to communicate control signal and data with the MS throughradio communication, and the wired interface is provided with a wiredcommunication means connected to a neighbor BS, a Mobility ManagementEntity (MME), and a Serving Gateway.

The control unit 1520 controls the resource allocation negotiationprocedure with the master BS and service provision to the MS incooperation with the master BS based on the negotiated resourceallocation information. In order to accomplish this, the control unit1520 includes a resource allocation negotiation controller 1520 a and acooperative transmission controller 1520 b.

If the resource allocation request message is received from the masterBS, the resource allocation negotiation controller 1520 a checks theresource requested by the master BS. The resource allocation negotiationcontroller 1520 a may determine whether to accept the resourceallocation request entirely or partially, or may reject the resourceallocation request in consideration of its resource headroom status, aconflict between the resource reserved for other MSs and the resourcerequested by the master BS, and a radio channel status.

If it is determined to reject the request, the resource allocationnegotiation controller 1520 a generates a resource allocation responsemessage including the reject indication and controls the slave BS tosend the resource allocation response message to the master BS.

Otherwise, if it is determined to accept the resource allocation requestfrom the master BS, the resource allocation negotiation controller 1520a determines whether there is any conflict between the resourcesrequested by plural master BSs. If there is no conflict, the resourceallocation negotiation controller 1520 a generates the resourceallocation response message including accept indication and controls theslave BS to send the resource allocation response message to the masterBS.

If there is any resource conflict, the resource allocation negotiationcontroller 1520 a may arbitrate to resolve the resource conflict andgenerates the resource allocation response message including thearbitrated resource allocation information. The resource allocationnegotiation controller 1520 controls the slave BS to send the resourceallocation response message to the master BS.

The cooperative transmission controller 1520 b controls the slave BS totransmit data to the MS in cooperation with the master BS and otherslave BSs based on the resource allocation information received from themaster BS.

FIG. 16 is a block diagram illustrating a configuration of a master BSaccording to another embodiment of the present disclosure.

Referring to FIG. 16, the wired/wireless interface unit 1610 provides awired and/or wireless interface for the master BS to communicate withthe MS or a higher layer network node through wired or wireless channel.In detail, the wireless interface is provided with a physical means forthe master BS to communicate control signal and data with the MS throughradio communication, and the wired interface is provided with a wiredcommunication means connected to a neighbor BS, a Mobility ManagementEntity (MME), and a Serving Gateway.

According to an embodiment of the present disclosure, the control unit1620 controls such that the master BS forms a virtual cell with pluralslave BSs. The control unit 1620 controls to generate the resourceallocation information through resource allocation negotiation procedurewith the slave BSs and provides the data communication service to the MSin cooperation with the slave BSs. In order to accomplish this, thecontrol unit 1620 includes a virtual cell configurator 1620 a, aresource allocation information generator 1620 b, and a cooperativetransmission controller 1620 c.

The virtual cell configurator 1620 a configures a virtual cell includingthe master BS and at least one slave BS. The BSs forming the virtualcell may communication data with the MS cooperatively in a diversitymanner or a multiplexing manner. As described above, the master BS maybe the BS to which the MS has performed the network entry process, butnot limited thereto.

The resource allocation information generator 1620 b sends the slave BSsthe transmissive data information. The transmissive data information maybe the allocation request message including the information on the sizeof data to be transmitted to the MS. The transmissive data informationmay also be the data itself to be transmitted to the MS.

The resource allocation information generator 1620 b receives theresource allocation response message and checks the content of theresponse message. If it is determined that the resource allocationrequest is rejected, the resource allocation negotiation controller 1620generates the resource allocation information in which the slave BSrejected the resource allocation request is ruled out.

Otherwise, if it is determined that the resource allocation request isaccepted, the resource allocation negotiation controller 1620 bdetermines whether there is any conflict among the resources accepted bythe plural slave BSs. If no resource conflict occurs, the resourceallocation negotiation controller 1620 b generates the final resourceallocation information to the MS. If there is any resource conflict,resource allocation negotiation controller 1620 b may arbitrate to avoidoverlap among the resource regions recommend by the slave BSs. Then, theresource allocation negotiation controller 1620 b transmits theconfirmation message including the arbitrated resource allocationinformation to the slave BSs. Afterward, the resource allocationnegotiation controller 1620 b receives the decision-making message fromthe slave BSs in response to the confirmation message.

The resource allocation negotiation controller 1620 b may send the MSthe resource allocation information determined finally through the aboveprocedure.

The cooperative transmission controller 1620 c controls the master BS totransmit data to the MS in cooperation with the slave BSs based on thefinally determined resource allocation information.

FIG. 17 is a block diagram illustrating a configuration of a slave BSaccording to another embodiment of the present disclosure.

Referring to FIG. 17, the wired/wireless interface unit 1710 provides awired and/or wireless interface for the slave BS to communicate with theMS or a higher layer network node through wired or wireless channel. Indetail, the wireless interface is provided with a physical means for theslave BS to communicate control signal and data with the MS throughradio communication, and the wired interface is provided with a wiredcommunication means connected to a neighbor BS, a Mobility ManagementEntity (MME), and a Serving Gateway.

The control unit 1720 controls the resource allocation negotiationprocedure with the master BS and service provision to the MS incooperation with the master BS based on the negotiated resourceallocation information. In order to accomplish this, the control unit1720 includes a resource allocation information generation controller1720 a and a cooperative transmission controller 1720 b.

If the resource allocation request message is received from the masterBS, the resource allocation information generation controller 1720 adetermines whether to accept or reject the resource allocation requestof the master BS. If it is determined to reject the request, theresource allocation information generation controller 1720 a generates aresource allocation response message including the reject indication andcontrols the slave BS to send the resource allocation response messageto the master BS. Otherwise, if it is determined to accept the resourceallocation request from the master BS, the resource allocationinformation generation controller 1720 a generates the resourceallocation response message including the resource allocationinformation and data transmission scheme information and controls theslave BS to send the resource allocation response message to the masterBS.

If a resource allocation confirmation message is received from themaster BS, the resource allocation information generation controller1720 a determines whether to accept the resource allocation modificationrequest included in the confirmation message. If it is determined toreject the resource allocation modification request of the master BS,the resource allocation information generation controller 1720 agenerates the decision-making message including the reject indicationand controls the slave BS to send the master BS the decision-makingmessage.

Finally, the slave BS transmits data to the MS in cooperation with themaster BS and other slave BSs according to the final resource allocationinformation.

FIG. 18 is a block diagram illustrating a configuration of an MSaccording to an embodiment of the present disclosure.

Referring to FIG. 18, the radio communication unit 1810 is responsiblefor radio communication function to transmit and receive data. The radiocommunication unit 180 may include a Radio Frequency (RF) transmitterfor up-converting and amplifying the transmission signal and an RFreceiver for low noise amplifying and down-converting the receivedsignal. The radio communication unit 1810 is also capable oftransferring the data received over the radio channel to the controlunit 1820 and transmitting the data output by the control unit 1820 overthe radio channel.

According to an embodiment of the present disclosure, the control unit1820 measures the radio channel states to the master BS and at least oneslave BSs forming a virtual cell and controls the MS to report themeasurement result to the master BS and/or slave BSs. The control unit1820 may also be capable of controlling the procedure of receiving thedata transmitted by the master and slave BSs of the virtual cell andtransmitting the data to the master and slave BSs based on the finalresource allocation information. In order to accomplish this, thecontrol unit 1820 includes a channel estimator 1820 a and a datatransmission/reception controller 1820 b.

The channel estimator 1820 a receives reference signals transmitted byBSs. The reference signals include a digital bit sequence for radiochannel estimation. The channel estimator 1820 a decodes the receivedreference signals to measure the quality of the signal propagated over aradio channel. The measured signal quality may be indicated by a SignalStrength, a SNR, or a SINR. The signal quality measured by the MS basedon the RS is referred to as Channel Quality Information (CQI).

According to an embodiment of the present disclosure, the channelestimator 1820 a may transmit the BS-specific CQI to the master BS (seeFIG. 5a ). Then, the master BS generates the resource allocationinformation based on the radio channel information between the MS andrespective BSs.

According to an embodiment of the present disclosure, the master BS maytransmit the BS-specific CQIs received from the MS to the slave BSsforming the virtual cell (see FIG. 8a ). The channel estimator 1820 a isalso capable of transmitting the BS-specific CQIs to both the master andslave BSs (see FIG. 8b ). This is because the detailed resourceallocation information of the MS is generated by the slave BS, in thecase of the embodiment of FIG. 6, and the slave BS has to check theradio channel information between the MS and the respective BSs.

The data transmission controller 1820 b control the MS to receive andtransmit data from and to the master and slave BSs forming the virtualcell based on the resource allocation information received from themaster BS.

As described above, the resource allocation method and apparatus of thepresent disclosure is capable of allowing pluralgeographically-distributed base stations having independentdecision-making right to negotiate resource allocation without anyhigher layer network node, thereby providing the mobile station withcooperative communication service efficiently.

At this point it should be noted that the various embodiments of thepresent disclosure as described above typically involve the processingof input data and the generation of output data to some extent. Thisinput data processing and output data generation may be implemented inhardware or software in combination with hardware. For example, specificelectronic components may be employed in a mobile device or similar orrelated circuitry for implementing the functions associated with thevarious embodiments of the present disclosure as described above.Alternatively, one or more processors operating in accordance withstored instructions may implement the functions associated with thevarious embodiments of the present disclosure as described above. Ifsuch is the case, it is within the scope of the present disclosure thatsuch instructions may be stored on one or more non-transitory processorreadable mediums. Examples of the processor readable mediums includeRead-Only Memory (ROM), Random-Access Memory (RAM), CD-ROMs, magnetictapes, floppy disks, and optical data storage devices. The processorreadable mediums can also be distributed over network coupled computersystems so that the instructions are stored and executed in adistributed fashion. Also, functional computer programs, instructions,and instruction segments for accomplishing the present disclosure can beeasily construed by programmers skilled in the art to which the presentdisclosure pertains

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method by a first base station for performingcooperative resource allocation with at least one second base station ina wireless communication system, the method comprising: transmitting afirst reference signal generated based on a first digital bit sequenceto a mobile station; receiving first channel quality informationdetermined based on a signal to interference and noise ratio (SINR) ofthe first reference signal from the mobile station for a resourceallocation; transmitting, to the second base station, a resourceallocation request message, wherein the resource allocation requestmessage includes information on a specific data to be transmitted to themobile station when the second base station retains the specific data;receiving, from the second base station, a resource allocation responsemessage including one of accept and reject indications to the resourceallocation request message; transmitting a resource allocationinformation generated based on the first channel quality information tothe mobile station; and transmitting a first packet, derived from datato be transmitted to the mobile station, to the mobile station incooperation with the second base station based on the resourceallocation information, wherein second channel quality information,determined based on a SINR of a second reference signal generated basedon a second digital bit sequence and transmitted from the second basestation to the mobile station, is transmitted from the mobile station tothe second base station for the resource allocation, wherein the firstdigital bit sequence is specific to the first base station and thesecond digital bit sequence is specific to the second base station,wherein the first packet is transmitted from the first base station tothe mobile station based on the first channel quality information,wherein a second packet, different from the first packet, derived fromthe data, is transmitted from the second base station to the mobilestation based on the second channel quality information and theinformation on the specific data, and wherein the first packet and thesecond packet is combined into data by the mobile station.
 2. The methodof claim 1, wherein the transmitting of the resource allocation requestmessage comprises requesting the second base station to allocate aspecific radio resource.
 3. The method of claim 1, further comprising:determining, after receiving a resource allocation response message,whether a change request for an allocated resource region exists in theresource allocation response message; and transmitting, when a changerequest exists, a resource allocation confirmation message including anindication on whether the change request is accepted by the second basestation.
 4. The method of claim 3, wherein the resource allocationrequest message comprises at least one of a number of resource blocks, aresource block index, a frame index, a subframe index, or data, whereinthe resource allocation response message comprises at least one of aresource allocation request accept/reject indication, a number ofresource blocks accepted, an accepted resource block index, an acceptedframe, or an accepted subframe, and wherein the resource allocationconfirmation message comprises at least one of a change requestaccept/reject indication, or a determined resource allocationinformation.
 5. A method by a second base station for performingcooperative resource allocation with a first base station in a wirelesscommunication system, the method comprising: transmitting a secondreference signal generated based on a second digital bit sequence to amobile station; receiving second channel quality information determinedbased on a signal to interference and noise ratio (SINR) of the secondreference signal from the mobile station for a resource allocation;receiving, from the first base station, a resource allocation requestmessage, wherein the resource allocation request message includesinformation on a specific data to be transmitted to the mobile stationwhen the second base station retains the specific data; transmitting, tothe first base station, a resource allocation response message includingone of accept and reject indications to the resource allocation requestmessage; and transmitting a second packet, derived from data to betransmitted to the mobile station, to the mobile station in cooperationwith the first base station based on the information on the specificdata and resource allocation information which is transmitted from thefirst base station to the mobile terminal, the resource allocationinformation being generated based on the second channel qualityinformation, wherein first channel quality information, determined basedon a SINR of a first reference signal generated based on a first digitalbit sequence and transmitted from the first base station to the mobilestation, is transmitted from the mobile station to the first basestation for the resource allocation, wherein the first digital bitsequence is specific to the first base station and the second digitalbit sequence is specific to the second base station, wherein the secondpacket is transmitted from the second base station to the mobile stationbased on the second channel quality information, wherein a first packet,different from the second packet, derived from the data, is transmittedfrom the first base station to the mobile station based on the firstchannel quality information, and wherein the first packet and the secondpacket is combined into data by the mobile station.
 6. The method ofclaim 5, wherein the determining of whether to accept or reject theresource allocation request comprises a determination based on at leastone of a resource headroom state, a conflict between resources reservedfor other mobile stations and requested from the first base station, ora radio channel status.
 7. The method of claim 5, wherein thetransmitting of the resource allocation response message comprises:determining whether a conflict exists among resources requested forallocation from plural first base stations; arbitrating, when a conflictexists, to avoid overlap among resource allocation regions; andgenerating the resource allocation response message including arbitratedresource allocation information.
 8. The method of claim 1, wherein thetransmitting of resource allocation information comprises: transmittingtransmissive data information for initiating resource allocationnegotiation to the second base station; and receiving a response messageincluding resource allocation information for data transmission to themobile station from the second base station.
 9. The method of claim 8,further comprising: transmitting, after receiving a response message,final resource allocation information generated based on the resourceallocation information transmitted to the mobile station; determiningwhether a conflict exists among resources requested by plural secondbase stations for allocation to the mobile station; arbitrating, when aconflict exists, to avoid overlap among the allocated resource regions;and transmitting a confirmation message including a change request forthe resource allocation information to the second base station.
 10. Themethod of claim 9, further comprising: receiving a decision-makingmessage from the second base station in response to the confirmationmessage; generating final resource allocation information based onacceptance or rejection to the change request included in thedecision-making message; and transmitting the final resource allocationinformation to the mobile station.
 11. The method of claim 8, whereinthe resource allocation request message comprises at least one of a datasize to be transmitted to the mobile station or a data transmissionscheme, wherein the response message comprises at least one of aresource allocation request accept/reject indication, a resource blockindex, a frame index, a subframe index, or a data transmission scheme,wherein the confirmation message comprises at least one of anaccept/reject indication to the response message, a changed resourceblock index, a changed frame index, or a changed subframe index, andwherein the decision-making message comprises an accept/rejectindication to the confirmation message.
 12. The method of claim 5,further comprising: initiating resource allocation negotiation with thefirst base station upon receipt of transmissive data informationtransmitted by the first base station; generating resource allocationinformation for data transmission to the mobile station; transmitting aresponse message including the resource allocation information to thefirst base station; and transmitting data to the mobile station incooperation with the first base station based on the resource allocationinformation.
 13. The method of claim 12, wherein the transmissive datainformation is one of a resource allocation request message includinginformation on data size and a data transmission scheme for resourceallocation through the second base station and the data to betransmitted to the mobile station.
 14. The method of claim 12, furthercomprising: receiving a confirmation message including a change requestfor the resource allocation information from the first base station; andtransmitting a decision-making message including an accept/rejectindication to the change request to the first base station.
 15. A firstbase station for performing cooperative resource allocation with atleast one second base station in a wireless communication system, thefirst base station comprising: a wired/wireless interface transceiverconfigured to perform wired/wireless communication with a mobile stationand neighbor base stations; and at least one control processorconfigured to: transmit a first reference signal generated based on afirst digital bit sequence to a mobile station, receive first channelquality information determined based on a signal to interference andnoise ratio (SINR) of the first reference signal from the mobile stationfor a resource allocation, transmit, to the second base station, aresource allocation request message, wherein the resource allocationrequest message includes information on a specific data to betransmitted to the mobile station when the second base station retainsthe specific data, receive, from the slave base station, a resourceallocation response message including one of accept and rejectindications to the resource allocation request message, transmit aresource allocation information generated based on the first channelquality information to the mobile station, and transmit a first packet,derived from data to be transmitted to the mobile station, to the mobilestation in cooperation with the second base station based on theresource allocation information, wherein second channel qualityinformation, determined based on a SINR of a second reference signalgenerated based on a second digital bit sequence and transmitted fromthe second base station to the mobile station, is transmitted from themobile station to the second base station for the resource allocation,wherein the first digital bit sequence is specific to the first basestation and the second digital bit sequence is specific to the secondbase station, wherein the first packet is transmitted from the firstbase station to the mobile station based on the first channel qualityinformation, wherein a second packet, different from the first packet,derived from data, is transmitted from the second base station to themobile station based on the second channel quality information and theinformation on the specific data, and wherein the first packet and thesecond packet is combined into data by the mobile station.
 16. The firstbase station of claim 15, wherein the at least one control processor isfurther configured to control requests of the second base station toallocate a specific radio resource.
 17. The first base station of claim15, wherein the at least one control processor is further configured to:determine, after receiving a resource allocation response message,whether a change request for an allocated resource region exists in theresource allocation response message, and perform transmitting, when achange request exists, a resource allocation confirmation messageincluding an indication on whether the change request is accepted to thesecond base station.
 18. A second base station for performingcooperative resource allocation with a first base station in a wirelesscommunication system, the second base station comprising: awired/wireless interface transceiver configured to performwired/wireless communication with the mobile station and neighbor basestations; and at least one control processor configured to: transmit asecond reference signal generated based on a second digital bit sequenceto a mobile station, receive second channel quality informationdetermined based on a signal to interference and noise ratio (SINR) ofthe second reference signal from the mobile station for a resource,receive, from the first base station, a resource allocation requestmessage, wherein the resource allocation request message includesinformation on a specific data to be transmitted to the mobile stationwhen the second base station retains the specific data, transmit, to thefirst base station, a resource allocation response message including oneof accept and reject indications to the resource allocation requestmessage, and transmit a second packet, derived from data to betransmitted to the mobile station, to the mobile station in cooperationwith the first base station based on the information on the specificdata and resource allocation information which is transmitted from thefirst base station to the mobile terminal, the resource allocationinformation being generated based on the second channel qualityinformation, wherein first channel quality information, determined basedon a SINR of a first reference signal generated based on a first digitalbit sequence and transmitted from the first base station to the mobilestation, is transmitted from the mobile station to the first basestation for the resource allocation, wherein the first digital bitsequence is specific to the first base station and the second digitalbit sequence is specific to the second base station, wherein the secondpacket is transmitted from the second base station to the mobile stationbased on the second channel quality information, wherein a first packet,different from the second packet, derived from the data, is transmittedfrom the first base station to the mobile station based on the firstchannel quality information, and wherein the first packet and the secondpacket is combined into data by the mobile station.
 19. The second basestation of claim 18, wherein the at least one control processor isfurther configured to determine whether to accept or reject the resourceallocation request based on at least one of a resource headroom state, aconflict between resources reserved for other mobile stations andrequested from the first base station, or a radio channel status. 20.The second base station of claim 18, wherein the at least one controlprocessor is further configured to: determine whether a conflict existsamong resources requested for allocation from plural first basestations, arbitrate, when a conflict exists, to avoid overlap amongresource allocation regions, and generate the resource allocationresponse message including arbitrated resource allocation information.21. The first base station of claim 15, wherein the at least one controlprocessor is further configured to: transmit transmissive datainformation for initiating resource allocation negotiation to the secondbase station, receive a response message including a resource allocationinformation for data transmission to the mobile station from the secondbase station, and transmit data to the mobile station in cooperationwith the second base station based on the resource allocationinformation.
 22. The first base station of claim 21, wherein thetransmissive data information is one of a resource allocation requestmessage including information on data size and a data transmissionscheme for resource allocation through the second base station and thedata to be transmitted to the mobile station.
 23. The first base stationof claim 21, wherein the at least one control processor is furtherconfigured to: transmit final resource allocation information generatedbased on the resource allocation information to the mobile station,determine whether a conflict exists among resources requested by pluralsecond base stations for allocation to the mobile station, arbitrate,when a conflict exists, to avoid overlap among the allocated resourceregions, transmit a confirmation message including a change request forthe resource allocation information to the second base station, receivea decision-making message from the second base station in response tothe confirmation message, generate a final resource allocationinformation based on acceptance or rejection to the change requestincluded in the decision-making message, and transmit the final resourceallocation information to the mobile station.
 24. The second basestation of claim 18, wherein the at least one control processor isfurther configured to: initiate resource allocation negotiation with thefirst base station upon receipt of transmissive data informationtransmitted by the first base station, generate resource allocationinformation for data transmission to the mobile station, transmit aresponse message including the resource allocation information to thefirst base station, and transmit data to the mobile station incooperation with the first base station based on the resource allocationinformation.
 25. The second base station of claim 24, wherein thetransmissive data information is one of a resource allocation requestmessage including information on data size and a data transmissionscheme for resource allocation through the second base station and thedata to be transmitted to the mobile station, and wherein the at leastone control processor is further configured to: receive a confirmationmessage including a change request for the resource allocationinformation from the first base station, and transmit a decision-makingmessage including an accept/reject indication to the change request tothe first base station.
 26. The method of claim 1, wherein thetransmitting resource allocation information comprises: transmitting, tothe second base station, a resource allocation request message includinginformation on a resource to be allocated to the mobile station;receiving a resource allocation response message including one of acceptand reject indications to the resource allocation request from thesecond base station; and transmitting, to the mobile station, a resourceallocation information including a result of resource allocationnegotiation with the second base station.
 27. The method of claim 5,further comprising: receiving a resource allocation request messageincluding information on a resource to be allocated to the mobilestation from the first base station; determining whether to accept orreject the resource allocation request of the first base station; andtransmitting a resource allocation response message including adetermination result to the first base station.
 28. The first basestation of claim 15, wherein the at least one control processor isfurther configured to: transmit, to the second base station, a resourceallocation request message including information on a resource to beallocated to the mobile station, receive a resource allocation responsemessage including one of accept and reject indications to the resourceallocation request from the second base station, transmit, to the mobilestation, a resource allocation information including a result ofresource allocation negotiation with the second base station, andtransmit data to the mobile station in cooperation with the second basestation based on the resource allocation information.
 29. The secondbase station of claim 18, wherein the at least one control processor isfurther configured to: receive a resource allocation request messageincluding information on a resource to be allocated to the mobilestation from the first base station, determine whether to accept orreject the resource allocation request of the first base station,transmit a resource allocation response message including adetermination result to the first base station, and transmit data to themobile station in cooperation with the first base station using theresource determined through resource allocation negotiation with thefirst base station.